(define (sum-use-iter term a next b) 
  (define (iter a result) 
          (if (> a b) 
              result 
              (iter (next a) (+ result (term a))))) 
  (iter a 0)) 
 
(define (square a) (* a a))

(define (cube a) (* a (square a)))

(define (inc a) (+ a 1))

(define (sum-cube a b)
  (sum-use-iter cube a inc b))
